Description: The long-term goals of this project are to examine the neural bases for recovery of motor function after a stroke and the effectiveness of rehabilitative training regimens on neurophysiologic and behavioral outcomes. These studies will use neurophysiologic and behavioral training techniques in adult primates to examine functional reorganization in the primary motor cortex after focal vascular infarct and the effects of rehabilitative retraining procedures on the extent and time course of reorganization and on functional motor recovery. Motor maps will be compared before and shortly after focal vascular infarct. Four specific aims will be addressed. Aim 1 will examine alterations in movement patterns during the recovery period and neurophysiologic changes that occur in the intact motor cortex. This study should shed light on the question of whether motor recovery is the result of relearning motor patterns used prior to stroke, or is the result of learning novel, compensatory motor patterns. Aim 2 will assess the effectiveness of different rehabilitative training regimens to optimize motor recovery after stroke. While many rehabilitative procedures are currently used in human stroke patients, this study could identify procedures which produce optimal functional reorganization in the motor cortex and optimal motor recovery. Aim 3 will examine the effects of repetitive manual skill training on motor maps and motor recovery following large ischemic infarcts. Previous studies using this monkey model used very small infarcts. It is not known if repetitive training is effective when a larger volume of cortical tissue is injured. Aim 4 will examine the effectiveness of delayed repetitive training after a stroke. Training procedures will be introduced either one or three months after a large ischemic infarct. This study will determine if there is an optimal window of opportunity to begin rehabilitative training in order to maximize adaptive plasticity in the motor cortex as well as motor recovery. These studies are designed to provide a clinical understanding for the recovery process after a stroke and the neurophysiologic effects of rehabilitation. The correlation of neurophysiologic reorganization with functional recovery after brain damage could eventually lead to new approaches to rehabilitative medicine.